help making a decision to buy a new subwoofer or not - diyAudio
Go Back   Home > Forums > Loudspeakers > Subwoofers

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 6th May 2005, 06:13 AM   #1
fazman is offline fazman  Canada
diyAudio Member
 
Join Date: May 2005
Location: Windsor Ontario
Default help making a decision to buy a new subwoofer or not

Hello all,
Wondering if I could get some opinions here (what better place to go right?)
First I apologize for the long post.
Iam currently running a QSC 1400 in bridged mode ( 500 watts mono into 8 ohms) to a JBL 2235H 15" low frequency driver in a 5 cubic ft. enclosure tuned to 30 hz.
For both home theater and music listening the results are pretty impressive although I have somewhat of a hard time mating it with my full range ported towers.
Someone told me that the JBL is not by definition a true sub and I would need to get a "real" sub to get the appropriate results.
Here is what I am considering:
Dayton Titanic MkIII 15" sub in a 3 cubic ft sealed enclosure, using my QSC in bridged mode ( now 800 watts into 4 ohms)
Does anyone think this is a good idea? I've heard good things about the Titanic I am just not sure if I should change what I now have.
I have also heard people talk about a sealed box being quicker and punchier than a ported one . Does anyone with some experience in this have some good suggestions? (BTW for home theater - 80 hz, and down, for music 40 hz. and down using the x-over in my Acurus ACT 3 pre pro.


Any opinions would be greatly appreciated

Dave.
  Reply With Quote
Old 6th May 2005, 07:02 AM   #2
diyAudio Member
 
Bill Fitzpatrick's Avatar
 
Join Date: Jun 2001
Location: Eugene, OR
I disagree with what you have been told. I would get another 2235 and run them in stereo. I'd do sealed in 5 cu.ft. each. The difficulty with mating them to your towers lies not with the woofer.
  Reply With Quote
Old 6th May 2005, 07:56 AM   #3
simon5 is offline simon5  Canada
diyAudio Member
 
Join Date: Nov 2004
Location: Québec, Québec
If you want to go with real subwoofers drivers, you could buy some Ascendant Audio Atlas 15 which are heavily discounted right now.
__________________
DIYaudio for President !
  Reply With Quote
Old 6th May 2005, 09:16 AM   #4
diyAudio Member
 
RobWells's Avatar
 
Join Date: Aug 2002
Location: UK
Your JBL models well against the 2226G used in the almighty subwoofer project here.

http://member.newsguy.com/~stigerik/almighty/index.html

Maybe you could try lowering the tuning freqency and building a slightly larger box.

As Bill said, 2 would be even better.

Cheers,

Rob
Attached Images
File Type: jpg jbljbl.jpg (42.3 KB, 220 views)
  Reply With Quote
Old 6th May 2005, 02:13 PM   #5
fazman is offline fazman  Canada
diyAudio Member
 
Join Date: May 2005
Location: Windsor Ontario
Quote:
Originally posted by RobWells
Your JBL models well against the 2226G used in the almighty subwoofer project here.

http://member.newsguy.com/~stigerik/almighty/index.html

Maybe you could try lowering the tuning freqency and building a slightly larger box.

As Bill said, 2 would be even better.

Cheers,

Rob
Hi Rob
Do you think making the box bigger and lowering the tuning frequency will give me better performance? JBL reccomends a 5 cubic ft, box with 30hz, tuning, maybe this is good for full range use and not sub use?
fs on the driver is 20 hertz, should I be tuning towards fs instead?
Thanks Dave
  Reply With Quote
Old 6th May 2005, 02:19 PM   #6
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
From everything I've heard the JBL drivers are pretty amazing. I wouldn't be quick to replace yours.
  Reply With Quote
Old 6th May 2005, 03:17 PM   #7
diyAudio Member
 
RobWells's Avatar
 
Join Date: Aug 2002
Location: UK
Quote:
Originally posted by fazman


Hi Rob
Do you think making the box bigger and lowering the tuning frequency will give me better performance? JBL reccomends a 5 cubic ft, box with 30hz, tuning, maybe this is good for full range use and not sub use?
fs on the driver is 20 hertz, should I be tuning towards fs instead?
Thanks Dave
Yes I do. JBL recommened enclosure is probably for PA use - doesn't factor in room gain. Lowering the tuning, and increasing the box size a bit will give you an EBS type roll off - should give you good extention, hopefully only 5 or 6dB down at 20Hz. Do a search for mike.e 's 2226 EBS on this forum to give you an idea.

A search on EBS and room gain should give you lots of info so you can make your own mind up.

Cheers,

Rob
  Reply With Quote
Old 6th May 2005, 06:03 PM   #8
fazman is offline fazman  Canada
diyAudio Member
 
Join Date: May 2005
Location: Windsor Ontario
Quote:
Originally posted by RobWells


Yes I do. JBL recommened enclosure is probably for PA use - doesn't factor in room gain. Lowering the tuning, and increasing the box size a bit will give you an EBS type roll off - should give you good extention, hopefully only 5 or 6dB down at 20Hz. Do a search for mike.e 's 2226 EBS on this forum to give you an idea.

A search on EBS and room gain should give you lots of info so you can make your own mind up.

Cheers,

Rob
Rob, Thanks for this info- I have never heard of an EBS alignment before. Just did some reading on it and it seems to make sense when designing a ported sub to go deep in a typical living room.

I'm starting to see the light and that there may be some NEW life given to my JBL. (BTW I do own a second 2235H but it is not in an enclosure, just don't have the physical space for it in my room)

I have had this sub for approx. 6 years now and although I liked it I just couldn't get myself to love it's really deep bass performance. Maybe the 30 hertz tuning frequency is why I am having trouble mating it with my mains?

I lack the skill/sosftware to design a new enclosure for them - is there anything you or any one could reccomend for box size and port tuning to get to my 20hertz tuning frequency?
I will be reworking my existing cabinets (adding more enclosure space)
Esthetics is not an issue as the box is hidden out of sight

Very much appreciated you guys know your stuff
  Reply With Quote
Old 6th May 2005, 06:46 PM   #9
simon5 is offline simon5  Canada
diyAudio Member
 
Join Date: Nov 2004
Location: Québec, Québec
How big can you go?

10 cu.ft internal net tuned to about 18.4 Hz with two 4" diameter Precision Port would be perfect but that's too big for most people hehe!

EDIT: I see you have a 2nd JBL 2235H, go isobaric my friend!
You can keep your enclosure as is. Just put a woofer bolted on the front of your enclosure exactly in front of your other woofer. You wire it out of phase so it's in phase with your other woofer. You will need to change the tuning of your box, use a single full-length 4" diameter flared Precision Port, for a nice 18.4 Hz tuning, remove the old port and put this one instead. You might need to block the old hole and drill a new one because the Precision Port is 18 inches long and need clearance behind it if possible.
__________________
DIYaudio for President !
  Reply With Quote
Old 6th May 2005, 08:10 PM   #10
fazman is offline fazman  Canada
diyAudio Member
 
Join Date: May 2005
Location: Windsor Ontario
Quote:
Originally posted by simon5
How big can you go?

10 cu.ft internal net tuned to about 18.4 Hz with two 4" diameter Precision Port would be perfect but that's too big for most people hehe!

EDIT: I see you have a 2nd JBL 2235H, go isobaric my friend!
You can keep your enclosure as is. Just put a woofer bolted on the front of your enclosure exactly in front of your other woofer. You wire it out of phase so it's in phase with your other woofer. You will need to change the tuning of your box, use a single full-length 4" diameter flared Precision Port, for a nice 18.4 Hz tuning, remove the old port and put this one instead. You might need to block the old hole and drill a new one because the Precision Port is 18 inches long and need clearance behind it if possible.
simon5
Interesting!
But I thought only woofers that typically work well in sealed enclosures work well in isobaric configurations ( high xmax huge rubber surrounds etc) Theres no doubt these JBL's were designed for ported enclosures.
Do you really think this kind of design would work well for what I have?
If so, Do I need to leave any space between the two woofers, won't the surrounds on the woofer interfere with each other?
Also , my cabinet now has 2 four inch diameter ports each 11 inches in length.
How long would I have to make this 4 inch precision port you talk about?
I like where you are going with this as I don't have to get out my wood working tools to completely change my box around.
I can just here my 2 year old now "DADDY DADDY COME PLAY WITH ME! NO MORE SPEAKERS NO MORE SPEAKERS!

Can any of you relate to this one!

Simon5 waiting to hear from you on this issue!
Any one else think this is a good idea?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Making Subwoofer - need expert help CamaroRog Subwoofers 9 8th May 2006 09:19 PM
Need help for making Subwoofer jithin Subwoofers 4 13th April 2006 10:21 AM
please help with decision.... Andy G Multi-Way 2 18th September 2005 09:49 AM
Making a subwoofer to complement Genelec 1029a VvvvvV Multi-Way 0 6th August 2005 03:40 PM
Tiny 12 litre subwoofer making 15Hz and 600ccm? ChocoHolic Subwoofers 37 14th June 2004 06:05 PM


New To Site? Need Help?

All times are GMT. The time now is 08:00 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2